Here is my 620g version of a Hex 3. It is made out of a silicone spinnaker fabric called Dynakote 75. It took me around 10hrs to make. It was computer designed and plotted on a laser cutter at the sail loft I work at.

I stuck it together using a japanese double sided tape, this has eliminated the need for seem sealing but has added aprox 100g to 120g to the final weight.

All photos were taken with a wind speed of 25+knts. It was extremly stable and has a taught pitch.

I used the tape to help join the panels. I'm a sailmaker so thats how I do things. It helps with acuracy but takes a bit longer to do. All seems are sewed with a double straight stitch. Tape can not take any load alone.

Rod,
They are a flat felled seem. Like building spinnakers I join the pieces using the seem stick first then sew. But when building sails we never use this seem EVER.

The camp site is right on the beach in the photos and it was very windy all night. I truly believe that the tipi held up so well because of the seems and the cloth orientated along the seems for strength.

Maybe when you get a chance you could put up something about the process you sailmakers use with tape for seams. Because judging by your seams and flawless pitch we all might have something to learn from you.